The present invention relates to electric door locking and releasing systems, which comprise electromechanical strikes installed in the doorjamb, providing adaptable comprehensive door locking and releasing functions. It is applicable for use with most door locks and to a wide variety of combinations of dead bolts and latch bolts.
Most main entry doors consist of two types of bolts, a dead bolt and a latch bolt. These two types of bolts provide different and necessary functions that together enable the normal operation of a modern main entry door. The latch bolt latches and holds the door in a closed position. It enables the user to push or swing the door closed and latched, and positions it for the dead bolt operation. The dead bolt, when locked, provides a secure and tamper resistant locking function.
Dead bolts usually have two detent positions, the locked position in which the dead bolt is extended out of the mortise in the door, and the unlocked position in which the dead bolt is retracted into the mortise.
There are two main kinds of latch bolts, the simple latch bolt and the complex latch bolt (the complex latch bolt is also known in the art as the dead latch bolt.) Latch bolts usually extend out of the door by a spring in the mortise. The simple latch bolt is an angular tongue-like bolt that operates against a spring in the mortise. The complex latch bolt is a similar angular tongue-like bolt that operates against a spring but also comprises a disabler element, collateral to the tongue-like bolt that operates against a second spring in the mortise. When the disabler element of the complex latch bolt is pushed into the mortise while the latch bolt is extended out of the mortise, the latch bolt is locked in its extended position and cannot be pushed into the mortise. This provides secure and tamper resistant functionality to the complex latch bolt overcoming a shortcoming of the simple latch bolt. This feature of the complex latch bolt prevents a potential intruder from opening the latch bolt by sliding a thin card such as a credit card between the door end and the doorjamb.
Providing integrated solutions to all types of bolts is necessary for a comprehensive adaptable electromechanical strike locking system to be useful. Prior art adaptable electromechanical strike locking systems do not control the releasing and locking of strikes for both latch bolts and dead bolts in a single system since different strikes would be necessary for each type of bolt and different controllers would be necessary for each type of strike. It is cumbersome for a user to operate more than one controller to open an electromechanical strike locking systems. The present invention simplifies the control of the electromechanical strike locking system by providing a universal strike for both the dead bolt and the latch bolt and a single controller. Prior art electromechanical strike locking systems have not addressed integrated fault tolerant mechanisms. A fault tolerant system, operating both the dead bolt and the latch bolt, is necessary for locking systems to operate reliably and provide confidence to the user of reliability. These deficiencies in the prior art may have hindered the wide acceptance of this technology, as users require dependable operation under any conditions. There is a need for a complete integrated system that addresses the need for better functionality and flexibility of electromechanical strikes and the compatibility with a wide variety of door lock configurations as addressed by the present invention.
Prior art electromechanical strike locking systems have not gained widespread acceptance and use because of deficiencies in reliability, the lack of fault tolerance capability, and the inability to operate them with an assortment of preinstalled locks in various configurations. Prior art electromechanical strike locking systems are difficult to install and operate because they lack the universality of the present invention, i.e., one type of strike for both the latch bolts and the dead bolts, and the ability to employ the same strike for left and right doorjambs.
These deficiencies in prior art electromechanical strike locking systems are not an issue in exclusive electromechanical strike locking systems, which have gained wide acceptance in business and industrial applications. An exclusive electromechanical strike locking system is a self-contained locking system, i.e., the mortise in the door and the electromechanical strike are installed together as one operable unit, which does not allow for interoperability with other existing locking systems. An example of one exclusive electromechanical strike locking system is the SDC series 50 manufactured by Security Door Controls of Westlake Calif. The system does not allow for interoperability with other locking systems and, therefore, is an exclusive electromechanical strike locking system. The present invention, in contrast, is an adaptable and comprehensive electromechanical strike locking system that works with a variety of existing locks by requiring only the retrofitting of the strikes in the doorjamb.
U.S. Pat. No. 4,017,107 to Hanchett, dated Apr. 12, 1977 (hereinafter “Hanchett '107 patent”) provides a strike frame for receiving a dead bolt or a latch bolt and to allow the bolts to move through a notch in the doorjamb. The Hanchett '107 patent discloses the use of a rotary pivoting shutter as a lock system. The system operates by means of a vertical rotary motion that opens and closes the strike.
U.S. Pat. No. 5,100,186 to Nordvall, dated Mar. 31, 1992 (hereinafter “Nordvall '186 patent”) describes the employment of a linear vertical motion of a strike within a chamber in the doorjamb. The vertical motion of the strike presents limitations for the operation of the latch bolt, in particular for the transverse movement of the latch bolts tongue against the strike. In addition the fixed size of the recess in the strike is not adjustable to receive different sizes of dead bolts. Additionally, the strike locking system described by Nordvall is not “universal” to left and right-hinged doors, and doors that open inwardly or outwardly. For example, in doors having a dead bolt and a latch bolt, a Nordvall strike locking system designed for a right-hinged door cannot simply be used on a left-hinged door without altering the relative positions of the dead bolt and latch bolt. In other words, the relative positions of the latch bolt and dead bolt must be reversed and the cutouts in the door jamb for right-hinged doors are necessarily different from that of left-hinged doors. This lack of symmetry requires different locking systems for left-hinged versus right-hinged doors and adds to the complexity and cost of manufacturing locking systems that can be used on all types of doors. The system described in the Nordvall '186 patent also does not provide a fault tolerant method employing closed loop control. In contrast, the present invention is universal to all left-right, inside-outside doors. It permits the control of the speed of the strike, the user can calibrate the travel distance of the strike, and it enables the use of a fault tolerant operation employing closed loop control. Further, the present invention, due to its horizontal motion, also operates with all types of latch bolts, thus, lending itself to a comprehensive lock system.
U.S. Pat. No 6,022,056 to Cope et al, dated Feb. 8, 2000 (hereinafter “Cope '056 patent”) discloses a door latch actuator that employs a spring latch plunger and a dead latch plunger to engage a spring latch bolt and its dead latch bolt pin, respectively. The spring latch plunger engages and retracts under the pressure the spring latch bolt and the dead latch plunger engages the dead latch bolt pin. In contract to the Nordvall '186 patent, the Cope '056 patent does not disclose the use of a movable strike within a receiver that securely engages either a latch bolt or a dead bolt. Rather, Cope discloses the use of movable “plungers” located within a receiver for engaging and pushing back a spring latch bolt and its corresponding disabler pin so as to unlock a door. This technique is completely different from techniques that incorporate a movable strike within the bolt receiver for securely retaining a bolt (latch or dead) within a chamber of the receiver.